The function accepts two positive integers ‘r’ and ‘unit’ and a positive integer array ‘arr’ of size ‘n’ as its argument,’r’ represents the number of rats present in an area,’unit’ is the amount of food each rat consumes and each ith elements of an array ‘arr’ represents the amount of food present in ‘i+1’ house number,where 0<=i

 

note: return -1 if the array is null

 

return 0 if the total amount of food from all houses are not sufficient for all the rats

 

input: r:7, unit: 2, n:8, arr: 2 8 3 5 7 4 1 2

 

output:4

 

class Food

{

static int packets(int r,int unit,int arr[]) public static void main(String args[])

{

int foodNeed=r*unit;//14 {

int start=0; int r=7;

int used=0;

int unit=2;

for(int f:arr) //5 int used[]={2,8,3,5,7,4,1,2};

{

start += f; 18 int result=packets(r,unit,used);4

used++;//4

if(start>=foodNeed)//18>=14 S.o.p(result);//4

{

return used; }

}

}

return -1;//not enough food

}

Here’s the solution based on  problem statement.

 

✅ Problem Understanding

r: Number of rats.

unit: Amount of food each rat consumes.

arr[]: Array representing food in each house.

We need to find the minimum index + 1 (1-based house count) such that the sum of food up to that house is enough to feed all rats.

If total food < required, return 0 (or -1 as per your original prompt).

If arr is null or empty, return -1.

✅ Example

Input:

r = 7

unit = 2

arr = [28, 35, 7, 4, 12]

Rats need = 7 * 2 = 14 units

 

Now sum up until the total food >= 14:

 

House 1: 28 → enough already → output = 1

 

But your sample input and output says:

 

input: r:7, unit: 2, n:8, arr: 28 35 7412

output: 4

 

It seems there might be a formatting issue (7412 likely meant to be 7 4 12). Let’s proceed assuming:

public class RatsFeeding {

public static int feedRats(int r, int unit, int[] arr) {

if (arr == null || arr.length == 0) {

return -1;

}

 

int requiredFood = r * unit;

int totalFood = 0;

 

for (int i = 0; i < arr.length; i++) {

totalFood += arr[i];

if (totalFood >= requiredFood) {

return i + 1; // 1-based house count

}

}

 

return 0; // Not enough food

}

 

public static void main(String[] args) {

int r = 7;

int unit = 2;

int[] arr = {28, 35, 7, 4, 12};

 

int result = feedRats(r, unit, arr);

System.out.println(“Output: ” + result);

}

}

✅ Output for the sample:

Output: 1

(Since first house already has 28 units, which is more than the required 14)

 

If you must match the output 4 as per your original message:

 

Then the assumption is:

 

arr = {2, 3, 4, 5, …} or something where food adds up slowly.

 

But from your numbers 28 35 7412, it seems they are just split incorrectly: 7 4 12.